This application relates to an ink jet cartridge or cassette as used in an ink jet printer, and more particularly to an apparatus and method for reducing the introduction of air into the system. It will be appreciated, however, that the invention may find application in related environments and applications that encounter these same issues.
It is generally known in the art to form a cartridge housing or body having one or more cavities or chambers that hold a predetermined supply of ink. For example, a single color of ink may be provided in a single chamber cartridge. Alternatively, multiple chambers may be provided, for example, each holding a different color ink stored therein for selective use in a color printer. It is also generally known to provide an ink absorbing member such as a reticulated polyethylene or melamine foam that fits within the chamber(s). In some arrangements, the ink absorbing member fills the substantial entirety of the chamber, while in other instances a portion of the ink supply is free ink and the remainder is stored in the ink absorbing member. In still other instances, all of the ink is stored as free ink in the cartridge. One or more outlet ports communicate with the respective one or more chambers through outlet passages. The outlet passage proceeds through a first or bottom wall of the housing. A supply needle from an associated printer extends through the outlet port and thus conveys ink from the housing to a recording head or printhead.
Print quality can be adversely effected by the introduction of air into the ink chamber or outlet passage. Thus, manufacturers of ink cartridges are careful in the design and assembly, i.e., filling, to limit the potential for air introduction into the system. One area of potential air introduction is through a seal member such as a grommet or septum that normally closes the outlet port. Seal members as used in commercially available cartridges are typically made from a porous material that allows permeation of both air and water. The entry of air through the seal member can dramatically effect performance of the printer, allowing air bubbles to form in the outlet port and creating print voids, or ink starvation problems.
Manufacturers have attempted to resolve the problem by using multiple seal members, e.g., use of a secondary seal over the seal member disposed in the outlet port such as a removable tape or film over the outlet port, or a tape/film that can be pierced by the supply needle associated with the printer. This secondary seal adds additional material, costs, and assembly to the cartridge in order to effect an improved seal at the outlet port.
Thus, a need exists to improve print quality and particularly limit the potential for air entering the cartridge through the outlet port.
The present invention provides an ink cartridge in which a housing has a chamber formed therein for receiving ink and a first or lower surface containing an outlet passage communicating with the chamber. An air-impermeable, nonporous seal member is received in the outlet passage for preventing air from entering the cartridge through the outlet passage.
The seal member is preferably formed of one of a rubber, polyvinyl chloride, thermoplastic rubber, or silicone rubber.
The seal member includes a thin membrane extending across and substantially perpendicular to a cylindrical portion that frictionally engages an inner wall of the outlet passage.
A primary advantage of the invention resides in the improved print quality that results.
Another advantage of the invention relates to the reduction of air introduced into the printing system.
Still other advantages and benefits of the invention will become apparent to those skilled in the art upon reading and understanding the following detailed description.